<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>背景图片</title>
  <style>
    .wrapper {
      width: 900px;
      height: 600px;
    }
    .box {
      width: 900px;
      height: 430px;
    }
    .a {
      background-image: url("./img/balloons.jpg");
    }
    .b {
      background-image: url("./img/star.png");
      background-repeat: no-repeat;
    }

  </style>
</head>
<body>
<div class="wrapper">
  <div class="box a"></div>
  <div class="box b"></div>
</div>
</body>
</html>